The president of a small manufacturing firm is concerned about the continual increase in manufacturing costs over the past several years. The following figures provide a time series of the cost per unit for the firm's leading product over the past eight years.

Year Cost$/$Unit $($$$)$ Year Cost$/$Unit $($$$)$

$120\mathrm{.}10526\mathrm{.}70$

$224\mathrm{.}40629\mathrm{.}90$

$328\mathrm{.}30731\mathrm{.}10$

$427\mathrm{.}40836\mathrm{.}10$